Probabilistic Risk Assessment of Airborne Laser Operations

N&R Engineering is currently partnering with NASA Langley Research Center (LaRC) on an ongoing project that seeks a high level of public safety for current and future NASA lidar systems.

To do so, N&R is enlisting a Probabilistic Risk Assessment to see how Earth’s inhabitants are being affected by our changing climate.

Project Outline:

NASA is a leader in atmospheric science and measurement. Research currently being conducted by NASA critically informs our understanding of Earth’s changing climate and how it directly affects Earth’s inhabitants.

N&R Engineering is working with NASA Langley Research Center (LaRC) to quantify the probability of ocular damage among the general public as a result of NASA’s airborne and space-borne lidar operations. Lidar works on the same principle as radar (and was coined as a portmanteau of light and radar) but uses laser light rather than radio waves or microwaves.

N&R is utilizing a probabilistic risk assessment (PRA) approach in order to ensure a high level of public safety for current and future NASA lidar systems. Two lidar platforms—one airborne and one space-borne—are currently being analyzed in detail:

HSRL-2 is a High Spectral Resolution Lidar project that includes the capabilities of DIAL (Differential Absorption Lidar). It is used to characterize the size, composition, distribution and movement of clouds and small particles in the atmosphere, called aerosols, in addition to providing ozone profiles, from various airborne platforms (e.g. NASA’s ER-2 and King Air aircraft).

MESCAL (Monitoring the Evolving State of Clouds and Aerosol Layers) is a joint effort to build a spaceborne lidar mission for studies of clouds, aerosols, and ocean ecosystems, which is being developed in collaboration with the French space agency, Centre National d’Etudes Spatiales (CNES).

Both of these laser systems are eye-safe for observers on the ground, but a potential hazard exists if the laser is viewed directly through magnifying optics (e.g. a telescope) or if viewed from another aircraft in sufficiently close proximity to a research aircraft. It is the potential for injury to these observers that is being analyzed.

Probabilistic Risk Assessment (PRA) is a comprehensive, structured, and logical analysis method aimed at identifying and assessing risks in complex technological systems. The purpose of this tool is to improve safety and performance in a cost-effective manner by quantifying the contributions of various factors to the overall potential for harm as well as the effectiveness of potential mitigation strategies.

N&R is following a paradigm of guided analysis that is generating successively more detailed and more realistic analyses driven by the lessons learned of the previous iteration of the analysis. This information will allow us to generate more realistic estimates of the risk of eye injuries, which will in turn guide mission planning to ensure operations are conducted safely.

N&R Engineering is performing this task as a subcontractor to MTECH, a prime contractor to NASA Langley for Mission Assurance.